Recently, various systems for providing viewers stereoscopic images are proposed.
In these types of image display devices, there are common systems that use binocular parallax to thereby provide, as three-dimensional images, two-dimensional images on an image screen of a display or the like.
However, in these systems using the binocular parallax, because a viewer watches a pseudo image as a three-dimensional image of a target object, the focus on the image screen and the convergence are off from each other, the viewer may be subjected to physiological effect.
Thus, as another system, an image display device, in which an image transfer panel (for example, a microlens array consisting of a plurality of lenses) is placed in front of a two-dimensional image at a predetermined space therefrom, for displaying a pseudo stereoscopic image (floating image) of the two-dimensional image onto a space in front of the image transfer panel has been known (for example, see a first patent document and a second patent document).
The image display device is adapted to focus the two-dimensional image by the image transfer panel while floating the two-dimensional image, thus displaying the two-dimensional image as if to display a three-dimensional image.    First patent document: 2001-255493    Second patent document: 2003-098479